Combining meter accuracy and reading variation for total uncertainty

Steps:

• Compute mean reading: (3.0 A + 3.08 A)/2 = 3.04 A (approximated as 3.06 A in choices).
• Determine variation uncertainty: half the range = (3.08 A - 3.0 A)/2 = 0.04 A.
• Calculate accuracy uncertainty: 1% of 3.04 A = 0.0304 A.
• Combine uncertainties: √(0.04² + 0.0304²) = √0.002524 ≈ 0.05 A.

Why C is correct:

• It applies the standard formula for total uncertainty as the quadrature sum of random variation and systematic accuracy, yielding 3.06 ± 0.05 A.

Why the others are wrong:

• A: Underestimates total uncertainty by ignoring full variation component.
• B: Uses only accuracy uncertainty (≈0.03 A), neglecting reading fluctuation.
• D: Misplaces mean at maximum reading and inflates uncertainty without quadrature.

Final answer: C